If
you can't get to Mars, then sending some sort of a signal to anyone
living there is the next best thing. At least, that was the
thinking of some Earthbound scientists of the late 19th and
early 20th centuries.

Of course, it wouldn't be possible to send anything
like intelligible messages; more like simple signs to show that their
was intelligent life on Earth, and that, as every good sci-fi reader
knows, meant geometry.

In 1893 the Reverend Lach-Szyrma proposed
signalling Mars by shining electric lights on the Rigi or the Malvern
Hills to form geometric patterns. He also proposed a more
flexible scheme for the Chicago Exhibition of stringing arc lamps
across Lake Michigan (pictured above) that could be shifted about to
form various geometric shapes to show that Earth was inhabited by
beings who were up on their Euclid.

The more modest London Magazine
proposal in 1907 suggesting building gigantic searchlights that could
flash coded messages at Mars or Venus seems downright sober by
comparison.

Mind
you, the publishers of the London Magazine seem to have been a
bit optimistic about the chances of someone catching their signals, as
they also depicted winged Martians lounging about in front of gigantic
view screens as they watched the happenings on Earth.

By the 1920s
bonfires and searchlights gave way to radio as the favoured means of
chatting with Martians. The eccentric
Nikola Tesla claimed to have
already received signals from Mars around the turn of the century.
Even Guglielmo Marconi expressed interest in Martian radio by 1919,
though he had reservations about attracting the attention of "superior
intelligences."

Today, we send radio signals into deep space as a
matter of routine to communicate with our unmanned probes to the
other planets, but we can manage that because we are able to send
tight-beamed, powerful, frequency-modulated signals that even a small
machine a billion miles away can pick up. In the '20s, sending
radio to Mars was a different kettle of fish. Radio back then
meant amplitude modulation and getting a signal to cover any sort of
distance was an exercise in raw power. Being able to shove a
signal as far as the Moon would have been an incredible feat and
getting it to Mars would have taken the output of the entire national grid.
Small wonder magazines that talked about radioing the planets depicted
giant installations like the one on the left on their covers.

Because of the
difficulties of calling Mars ourselves, Professor David Todd of
Amherst College suggested that the better approach would be to listen
for what the Martians were transmitting to us. There was one
problem, however: how to hear the Martian broadcasts with so many
Earth stations to drown them out?

In 1924, when Mars was in opposition with the
Earth, Todd proposed two days of worldwide radio silence so that
scientists could listen for the Martians. It says something for
Todd's powers of persuasion that he was able to get the US Army and
Navy to shut down their sets for two days, though his appeals to
private broadcasters resulted in only WRC in Washington DC going off
the air.

The results were less than less than encouraging.
Todd tuned his receivers to a frequency that was so low that any
incoming signals would have been unable to penetrate the Earth's
atmosphere. Many of those listening for the Martians heard all sorts
of strange clicks, whines, whistles, and buzzes, but anyone who has
spent time with a shortwave set will understand that these all turned
out to be the usual static and atmospheric effects that radio is
prone to. Anyone listening in the vicinity of Louisville,
Kentucky, however, would have had something more alarming as WHAS was
carrying an unscheduled live broadcast of local artillery exercise
that featured some of the most remarkable noises ever heard on radio
as the cannon reports overwhelmed the primitive transmitters.

In the end, the two-day listening fest was declared
a wash. When the great Charles Steinmetz did the maths and
revealed the incredible power it would take to punch a signal across
space with the technology of the day that was pretty much the end of
the matter for the next twenty years until the development of radio
astronomy.

One person who did not lose heart over this was the
82 year-old French astronomer Camille Flammarion, who declared that he
believed that the Martians would still try to contact us... by
telepathy.